Proper grooming of golf course greens seeks to maintain consistent playability of the grass surface, and to eliminate “grain,” texture in the green that can bias the roll of the golf ball. If the leaves of grass in the green are oriented in a particular direction, such as can naturally occur in response to the direction of sunlight, balls hit in the direction the grass is leaning, or “with the grain,” face less resistance to their rolling than balls hit in the reverse direction, or “against the grain.” Grooming the grass in the green to stand straight involves maintaining precise cutting height and reducing to the greatest extent any factors which would introduce a non-vertical orientation of the grass leaves.
The design of modern reel mower cutting units utilizes a powered reel of several helical blades which rotate in close contact with a fixed bedknife to clip the grass leaves to a uniform height in a scissorlike fashion. The number of blades in a cutting reel varies, with more blades providing a greater “clip frequency” over a given distance of the reel mower cutting unit's forward travel. The cutting reel and bedknife are generally mounted between two ground-contacting rollers in a frame that permits the height of cut to be adjusted precisely. In walk-behind reel mowers, the rear roller, also called the traction roller, is powered, and the front roller is generally used to adjust the cutting height. In current walk-behind designs, the cutting reel is either mechanically linked to the engine and drivetrain powering the rear traction roller, or is powered by an electric motor which permits the clip frequency of the cutting reel to be set independent of the engine's throttle setting and speed of ground travel, an arrangement termed a “hybrid” drive.
In ride-on reel mowers, one or more powered helical reel cutting units is pushed or pulled across the grass surface by a tractor, with each cutting unit mounted on its own ground-contacting rollers in a manner that permits the cutting units to individually adjust to the contours of the ground. Hybrid drive systems are also available for the cutting units of ride-on reel mowers.
Powered rotating brushes are known which may be used to keep the ground-contacting rollers of the reel mower free of grass clippings, which could otherwise adhere to the rollers and change their effective diameter, resulting in a change in the height of the cut. For example, uneven cutting could result from clumps of grass clippings adhering to the rollers, producing “bumpy” or “washboard” greens.
It is also known in the art to provide a mechanical means for conditioning the grass leaves prior to cutting, generally through the use of a rotating powered brush or set of rotating vertical dethatching blades located between the front roller of a reel mower cutting unit and the helical cutting reel. Many reel mower cutting units have a groomer drive accessory configured to power such turf conditioning attachments. Such conditioning means are intended to take advantage of the natural plasticity of the grass leaves in order to temporarily re-orient them in a more vertical direction immediately prior to cutting. Changing the orientation of the grass leaves, such as through brushing, increases cutting effectiveness by helping to ensure that grass leaves do not pass below the blades of the cutting reel and thus escape cutting. Mechanically conditioning the grass prior to cutting can, with repeated application, also train the grass leaves in the green to a more upright growth habit.
Existing mechanical means for conditioning the grass prior to cutting are, however, inefficient for their intended purpose, and can introduce “grain” and other problems into the reel mowing process. Existing conditioning means which use rotating dethatching blades provide little “lift” to the grass, because the blades are intended primarily to cut the stolons connecting individual grass plants, rather than re-orient the grass leaves. Existing powered brushes for conditioning the grass prior to cutting, such as the helical brushes offered by Deere & Company, Inc. (One John Deere Place, Moline, Ill. 61265-8098) and The Toro Company, Inc. (8111 Lyndale Avenue South, Bloomington, Minn. 55420-1196), are also inefficient, and their helical design can introduce grain, by “augering” the leaves of the grass preferentially in one direction. If applied aggressively, the “augering” effect of a helical brush design in contact with the turf can even affect the steering of the mower in walk-behind models.
Earlier designs for powered brushes having continuously bristled surfaces were less effective at penetrating the grass canopy, and earlier powered brushes having discrete tufts of long bristles used too few rows of tufts for optimum effectiveness, and the long bristles tended to flex too much and wear out faster. Other techniques, such as the use of separate grooming equipment prior to mowing do not address the compaction of the turf and compression of grass leaves caused by the front roller of the reel mower cutting unit, and a delay between grooming the turf and mowing permits the grass leaves time to relax prior to cutting.
A need therefore exists in the art for an improved powered turf conditioning brush for conditioning the grass prior to cutting that provides increased efficiency, improved lift, and which minimizes the introduction of grain.